Taking BPA out of water

RESEARCHERS have described a quick and cheap technique that they say removes 99% of toxic bisphenol A (BPA) from water in just 30 minutes.

Described as a “large-volume, everyday-everywhere” chemical, BPA can affect human health even in low doses. It is found in a wide variety of consumer goods, such as in water bottles or DVDs, or in epoxy resins. As it ages, molecules are released, and can be found in soils, sediments, sewage sludge, air and drinking water. This has been linked to a range of health problems in humans and wildlife, such as developmental issues and cancers, as it mimics the hormone oestrogen.

The case for treating water sources to remove BPA, and a novel treatment to do so, has now been made by researchers in Green Chemistry. The interdisciplinary team say their method can quickly and cheaply remove more than 99% of BPA from water on a small or large scale.

Terrence Collins, professor of green chemistry at Carnegie Mellon University, US, said: “The massive global use of BPA burdens an already overstrained water treatment infrastructure and most BPA water releases simply never reach a water treatment facility. Our approach has high potential to be a much better remediation strategy for BPA-contaminated waste streams.”

Their method involved a group of catalysts called TAML activators: small molecules that mimic oxidising enzymes. Adding TAMLs and hydrogen peroxide to water heavily contaminated with BPA resulted in a 99% reduction of BPA within 30 minutes at near neutral pH – the pH typically used in wastewater treatment.

During treatment, BPA assembled into oligomers, which clumped together and precipitated out of the water. The authors have said that the clumps could easily be filtered out on a larger scale, and further study showed that they were not harmful, and did not revert back to BPA.

Collins told the New Scientist: “We’ve solved a billion-dollar research problem. This treatment can be done by anyone, anywhere, on any quantity of water.

“You can treat tens of thousands of tons of water with 1 kg of the catalyst,” he added.

The researchers also tested their treatment at a pH of 11. They found that BPA reduction was >99.9% within 15 minutes, and BPA molecules did not form oligomers, but were in fact destroyed.

Collins said: “Because TAML/hydrogen peroxide treatment eliminates BPA from water so easily at concentrations that are similar to a variety of waste streams including paper plant processing solutions and landfill leachate, assuming the lab studies transfer to the real world, we can now offer a new and simple procedure for reducing BPA exposures worldwide.”

 Green Chemistry: http://doi.org/cbbx